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The Last Gunslinger writes "Tom's Hardware Guide has published an article (complete with video) showing how they employed their own approach to the liquid cooled computer. To offset the loss of normal airflow around their Athlon FX-55 and GeForce 6800Ultra, the mad scientists in the lab decided to fill the case up with 8 gallons of cooking oil. The oil temperature leveled off at a comfy 104F during benchmarking operations intended to tax both the CPU and GPU to their limits. Interestingly enough, they first attempted this operation using deionized water. It worked for 5 minutes before developing short circuits...but the hardware was amazingly undamaged." Slashdot has covered similarprojects in the past but it was neat to see the differences in oil and the look at capacitance around the CPU pins.

They admitted in the article that there are better kinds of oil for this kind of setup, and that one would have to clean the parts after taking them out. This was just proof of concept, I guess.
I still find it pretty cool, since there are no moving parts, and it is probably "a tad" cheaper than the fanless cases Zalman sells...

if it's good enough for x-ray and broadcast transformers and particle accelerators, it's good enough for your pc. it's less likely to grow crud, very much less likely indeed to harbor water, and readily availiable.

Actually I used to use Shell DialaAX in the laser power supplies I used to build. It is mineral oil based, but it has stablizers in it that makes it last and not oxidize.
The best (but most expensive) solution is 3M Flourinert. We use FC-77 at my place of business. But it's $350 for 11 lbs. (about 3/4 of a gallon).

Oil comes with some problems. It is more viscous (thicker) than FC-77, so it won't circulate or flow as well, it's a lot less dense and has a lot lower specific heat. This means that it won't cool as well.
It's also a huge mess. Everything gets covered in it. It will slowly leach through even the tiniest of cracks. Any oil that collects on the ouside of the case will attract dust and dirt. It attacks many plastic and rubber materials including most silicone sealants. I remember it causing one type of shrink tubing to expand to about 2 times it's length. Some capacitors unwrapped themselves, and I've known some people to be mildly allergic to it.

FC-77 on the other hand is beautiful to work with, (other than the cost). It's water clear, when you remove the electronics from the tank, the FC-77 evaporates away in a few minutes leaving absoultly no residue. It boils at 97 deg C. So if you have a really hot part, the boiling (phase change) takes away even more heat. It attacks almost nothing (inert). Won't stain, or mess up your carpet and is practically non-toxic. You do need to protect it from evaporation though.

Just a note on De-ionized water, anyone who ever worked with it knows it's very corrosive. It tries to bond with ions in anything it can get it's hands on. It dosn't stay deionized for very long if it's in contact with any metals.

Fluorocarbons are great — it's what Cray user — but there can be some problems. Besides the cost, that is. I say this as someone who spent six months retrofitting a flow cytometer [flow-cytometry.de] to run with various fluorocarbons, and I can say from experience that it isn't always straightforward.

Highly inert though they are, fluorocarbon liquids can damage teflon and other fluorocarbon plastics and rubbers, as well as many epoxies. This isn't as dramatic as acetone on acryllic, but teflon will swell and sof

Just because there was oil in the PC, and the CPU was cooled, it doesn't follow that the oil did the cooling. It could be that CPUs that drop in temperature exude oil or that there is some other factors that caused both the cooled CPU and the appearance of oil.

At Los Alamos National Lab, an early star wars prottype, the Beam aboard a rocket program launched a sub orbital sattelite that had electronic dissipating lots of heat for a short interval. Fans don't work well in space. And weight was a premium. The solution was to fill it with parafin. The parafin not only conducted the heat as a solid/liquid but it also has a phase change from solid to liquid which until the transition was 100% liquid clamped the electronics at the melting temperature of the wax. This required no circulation pumps.

Of course once it all melt then you are back to the steady state conduction of liquid parafin. But if you've ever made candles then you know that melting 8 gallons of wax on a stove burner can take a long time. If you can make that last say 12 hours--a work day-- and then let it cool down overnight you might never melt it all (or have two computers and play ping pong: one always cooling while the the other is heating).

That's a pretty interesting idea. Normally when we think of phase-change cooling it's liquid to gas and vice versa, but solid to liquid phase change is certainly an option too.

What I wonder about though, is whether in a conventional (atmospheric) application, you would end up with voids in the parafin (or other material with low melting point) as it heated and cooled. Obviously this would be a bad thing and could lead to overheating of the chips. I don't know much about the physical properties of parafin -- does it expand and contract as it heats and cools? If so then it seems like it could easily form voids around the chips.

I once worked with a liquid, some sort of long-chain polymer, that had a freezing point of around 40F. If you chilled the whole thing slightly below it's freezing point, that might be able to work in much the same way. Provided of course that it's a dielectric.

Of course, once the oil turns rancid, things could get interesting as well as smelly...

I thought the same thing -- interesting concept, but cooking oil would either have to be changed every few days or so, or it would get stinky. Of course, they included a plug at the bottom of the case to make draining the oil easier.

They say at the end of the article that they recommend motor oil for long term operation. They used cooking oil for proof-of-concept. I still don't know if I would want the top of the case open as they did, even with motor oil, so I guess some sort of heat exchanger would have to be included to run this with a totally sealed interior. You'd need something to keep the oil at 104 deg F or cooler with the top on -- I'm sure it wouldn't be that hard to design something.

That's fully synthetic mineral oil for the hydraulic suspension, braking and steering used in Citroën, Rolls-Royce and some Audis. It's very thin, clear, bright green oil, and it's (relatively) cheap. It's also non-hygroscopic, which would be good here, and doesn't attack rubber and plastics (which is sort of the whole point, otherwise the hydraulics would pish fluid all the time).

These five things will slowly reduce the quality of your oil, forcing pre-mature replacement, and adversly affecting the taste^W [operation] of the product^W [computer].

Salt is introduced into the oil when [you eat] the french fries are salted too close to the vat^W computer. This has immediately damaging affects on the oil. Always ensure that you salt the fries [you are going to eat] in the bin^W^W^W [on your desk] rather than over the vat^W [computer].

Water is naturally introduced into the oil from the air around us, and the moisture contained inside the french fries.^W^W^W^W^W^W^W^W Try to shake off excess ice before cooking the fries.

Since air is all around us, there is not too much that can be done to stop this enemy of oil. However, keeping the lid on the vat^W [computer] when not in use has been shown to reduce oxygenation of the oil.

Carbon is introduced into the vat^W [computer] as the french fries are cooked. Use the handheld strainer to remove excess carbon from the vat^W [computer].

Heat is a constant threat to the oil. Since the french fries are often cooked at 400 degrees or higher^W^W^W^W^W^W^W^W^W^W^W^W [Since the computer regularly operates at temperatures rivaling a nuclear power plant], it is important to constantly monitor the clarity and viscousness of the oil. Use of a portable strainer can remove destroyed oil, and allow you to rescue the oil that is still in good condition.

Follow these simple tips, and your french fries^W^W [computer] will remain tasty batch after batch!

I should call 3M and see if they can find me a non-conductive, inert, non-volitale chemical to submerge a PC in. I'm sure they make one.

You should. But I'll save you the trouble.

It's called 3M Fluorinert, and now that it's come up in two separate discussions in two days, I now know more about the stuff than I ever wanted to. (Great use of company time, eh?)

This is the 3M page about it, they make a bunch of different varieties for various purposes. I believe what you'd want to use on a computer is the '77' variety. (I'm told that's what the Cray II used.) 3M Fluorinert [3m.com]Some people [parallax-tech.com] who will sell it to you in small quantities (3M wants you to buy 11 lbs.)And here's the obligatory Wikipedia entry: http://en.wikipedia.org/wiki/Fluorinert [wikipedia.org]

Fluorinert is utter overkill for this application. It's designed to take high temperatures and react with almost nothing (and I once boiled away a litre owing to a bug in our PID controller loop, sorry folks, blame assembler coding.)

You probably don't want something too flammable, but if you can seal well enough to keep water out isopropanol is relatively nonvolatile and nontoxic, it's just that alcohols tend to absorb water. (Another option is propylene glycol, the stuff used in nontoxic marine antifreeze.

I'm sure in hindsight it's a dumb thing to try, but sometimes you can get unexpected results. I think there was probbably enough garbage on the motherboard to provide enough ions to establish a current. I wonder what would have happened if they had rinsed the motherboard first.

They do nice hardware reviews but are otherwise clueless (admittedly like most of us are outside the respective areas of our individual expertise). Weren't these the same people who tried to liquid nitrogen cool a fluorinert loop for overclocking and didn't think before buying it whether the fluorinert might just freeze solid at LN2 temps (77K)? Duh. It would not matter in the least if the boards were rinsed before this was tried. Ultrapure deionized water has a theoretical resistivity of 18 MOhm/cm, pretty

The pcb material will swell over time. You know all those little thru vias that connect traces between the layers of the pcb? They don't stretch so good. That faint popping sound you hear is the vias seperating, and then bye-bye pcb.

A really good clue that your motherboard is dissolving/swelling is when the oil turns the color of the motherboard...

Funny how this same topic comes up regularly, and yet there seems to be no progress in forseeing the problems.

I don't know, the last place I worked at had a LASER welder that used De-ionized water flowing over the flash lamp (~400 volts) to keep the bulb at a set temperature. We would buy distilled water from the grocery store and change the water about once every 3 months. What probably made the difference though was that there was de-ionizing resin in a chamber that the water would flow through on its way to the Flash Lamp. It was really expensive if I remember correctly. I don't know much about it, but it consisted of really tiny plastic like beads about.5mm in diameter that also had to be changed at the same time as the water.

This is one of those moments that I wish I could work at a Dunkin Doughnuts. I could deep-fry doughnuts from the heat of a dual-core AMD CPU and quad-core Nvidia video card and play Quake 4 at the same time.

Not sure why you'd want to do this. The benefits (effective, silent cooling) are more than negated by the drawbacks.For example, if you get water into the system you could fry your machine. Its not that difficult, especially if its not sealed too well. Another example being if the sealing were to catastrophically fail, you'd have 8 gallons of cooking oil that wanted out, and if you weren't at home could very well destroy the board.

Think you're going to try to take this thing to a LAN party? Good luck.

How's the buff Asian guy next to you going to feel when he and his machine are doused in cooking oil?

Wow, I could take this and run with it in one of two directions. I could laugh at you for implying that either of the two buff asian dudes in the country would be at his LAN party but I think I'll comment on how I'd rather see a hot asian chick get doused in oil. Mmmmmm, oily asian chicks.

If you read the whole article, they say on the last page that Motor Oil would be better than Veggie oil. But 5 gals of 1W/30 oil would be expensive!!! I wonder if synthetic oil would be better than petroleum based oils?

There was one experiment covered on Slashdot a looong time ago in which the person used mineral oil. Full emersion cooling has a major problem in that it would be easy to get backwaters in which there is little or no circulation. Air bubbles can also be a headache, for a similar reason.

You've got to watch the thermal range, if you're wanting to do extreme cooling OR run really hot hardware. Some of 3M's synthetic liquids are excellent for this type of project - well, they would be but only a handful of enthusiasts have ever been able to afford them.

Finally, although you only need to extract the amount of heat being put into a total emersion system, you've got to cycle through most/all of the liquid in a reasonably short period of time. You shouldn't rely on the heat simply transferring through the liquid. Besides, if you do that, some regions will be hotter than you'd like and others colder, even if the average is just fine. The average doesn't matter, because no component will see the average.

Wait, I've got a better idea, let's convince Tom's Hardware to try out kerosene or gasoline. Though I imagine the volatility of gasoline would be a problem (well that and flammability issues...)

Gasoline is neither volatile or flammable. This is important to remember when handling it. You may be treating that canister with kid gloves, but it's the fumes that you carelessly let evaporate out of the can that's going to singe your eyebrows off. Keep the lid on your computer, work in an open area with lots of ve

I always thought gasoline was considered volatile in that it readily evaporated into those fumes of which you speak. I don't have any numbers (or any facts beyond high school chemistry really) but it seems like you'd have to keep the case very tightly sealed or else it'll leak flammable gasoline fumes constantly. Anyway, this is all pretty moot since I'm certainly not filling my ATX case with gasoline any time soon.

I believe oil only seriously burns in the presence of oxygen (oil is not a chemical explosive that can burn without an oxygen supply). So this case would just need to be airtight or near airtight to be safe from this, and guess what: you need to do that any way to prevent leaking.

Oil has to be hot to burn. Unless you're cracking open an arc lamp I doubt you'll have enough heat to do anything. The only reason veg oil burns in a diesel engine is that the compression ratio is so high (22:1 before the turbo spools up in my mercedes.)

This is not new [digg.com] and was probably done even before the digg article post, which was made over 180 days ago. I seem to remember coverage on slashdot or somewhere else about this being done several years ago.

I think that we're going to see more stuff like this in the future. I don't think vegetable oil is where it's going to be though -- there are a lot better liquids that you can use, which conduct heat far more effectively. I found a place within a few minutes of googling that is willing to sell anyone 1gal or 5gal jugs of light white mineral oil (a petroleum product) for relatively cheap, in various viscosities. I think that would make a lot more sense than using some sort of organic oil that's going to go bad.

And if you were going to use it in anything serious, you'd really want to get 3M Fluorinert. It's expensive as hell, but it's designed for exactly this purpose.

That seems like an awfully short time period to have leached out enough material to allow current to flow. I wonder what they did to clean the circuit boards of residue prior to filling the box with water?It probably says in the article but I'd hate to defy etiquette and actually read it.

It's not the water that damages electronics but rather the salts and other ions in the water that allow short-circuiting, and if concentrations are as high as in tap water will often leave conductive salt bridges between pins. (Washing ciruit boards in the dishwasher can be ok, though, if you know what you're doing.)

Deionized water temporarily has no ions but disolves some out of virtually anything, making it an undependable resistor. It also has a whopping dielectric constant that would be a bad idea in any case for a bath for high-frequency circuits designed to run in air.

My understanding is that DI water reacts with itself to form ions of water, called hydronium and hydroxide. Thus, you can't store DI water for long - it turns into ordinary distilled-quality "water" pretty rapidly. Water has to have salts in it to be conductive, but water which is not DI is still corrosive.

Tranformers have used oil for a very long time for cooling. The problem with putting it in a computer case is that over time the oil would most likely work its way into the slots on any cards you have installed and cause the system to stop working. And you have the maintance problem, you want to upgrade that video card but now you have several hours job of draining the oil, removing the existing card, cleaning the slot connectors carefully, installing the new card, sealing the system up, refilling with oil, only to find out that you forgot to set the options on the card correctly, back to step one.

BTW: I saw a tranformer on a pole catch fire once. Spit oil and other stuff all over the cars below it. Very impressive.

Transformers, breakers, 500KV transformers in fact just about every piece of utility equipment use transformer oil.So did the Heathkit dummy load. A 1 gallon paint can to be precise. It used an SO-239 connector gasketed to the top.

With the proper gasket and connectors this will work well. Actually I might suggest a vertical Pelikan case not too different looking from an ammo case. As for fires that is generally 20 year old oil in overloaded transformers. So when was the last time you fired up your Appl

you want to upgrade that video card but now you have several hours job...

That also brings computers closer to being an "appliance" with no user-serviceable parts inside, though....which, for some manufacturers is a plus. Just saying "don't touch that" has clearly had no effect on the various geeks of the world. Saying, instead, "Hot oil inside...don't open or you'll be burned" will deter a much larger number of geeks. Not all (there's always one), but still...

Speaking of appliance, I would like to find a cheap system with at least S-video out for use with a TV to act as a front end system for mythtv. No moving parts. Network bootable. Would be nice to have mpeg2 decoding on the video output. The epia systems get close but are fairly expensive.

When I first heard of submerging a computer in oil I Googled the web to see if anyone had successfully done it. I came across a discussion board where a high school kid wanted to use the idea of computer cooling for his science fair project. He wasn't, however, keen on destroying a perfectly good computer with oil. He asked the group if submerging the computer in ethanol would be a better choice, since it would evaporate off when he was done.Someone in the discussion said, while the cooling properties of al

Someone in the discussion said, while the cooling properties of alcohol are well known, and his hardware would likely come clean, the possibility of fire, and probably even large explosions wouldn't make it worth while.

What not worth it! Sounds like an fun thing to try. Large explosions are always worth it. Maybe someone should submit it to Myth Busters.
--
Q

Looks like Comer wasn't so far off with his water dunked rig after all. Strange noone has posted this old avforums gem [avforums.com] in this thread yet.

I decided this weekend to try and quiten my PC by following some other members lead and going down the water cooling road. The fans on my PC were really starting to drive me mad. The first thing that I did was to remove all the fans. The one on the processor and graphics card were no problem but the one in the power unit was a bugger to get out.

The most difficult part was sealing all the ventilitation openings in the PC case with silicon. I also put silicon all around the joints on the PC case. The smell of silicon was dreadful but when my wife complained I told her to be patent as it will be worth it when we have a completely silent PC.

Because I had completely sealed the PC case the only opening near top was the DVD drive. So I opened that and put the small hose I had purchased specially for the job into the DVD drive as far as it would go. With what I can only describe as great excitement and anticipation, I turned on the water. It really is amazing just how long it took before the case was complete full, and boy was it heavy. That didn't really bother me as I didn't intend to be moving the PC anyway.

The big moment had arrived so I called in my wife and mother in law (who was visiting) and I announced "prepare to hear nothing!" and flicked the switch on the socket on the wall.

Before I could even press the power button on front of the PC, with a loud bang, the whole place was plunged into darkness

I knew that it was only the tripswitch so I told my onlookers not to panic and I ran out to the hall to turn the trip switch back on. But can u believe it, it wouldn't stay on. After five attempts I decided to try unplugging the PC and would you believe...yes the trip switch stayed on. My conclusion: the PC must have in some way been causing the problem.

After about an hour of tries I finally decided to abandon the whole idea of water cooling and emptied the water out of the PC, put back in the fans (except the fan in the power unit, I had broken that one getting it out) and tried the pc AGAIN. IT STILL CAUSED THE TRIP SWTICH TO BLOW!

My PC is completely shagged thanks to stupid suggestions that I got on this forum. What the hell am I going to do now. I spent two hours last night with a hair drier inside the PC case and it still trips the switch.

There is non-silicone DOT 5.1 brake fluid [boomplustoys.net]. And even IT ain't compatible with the silicone stuff, though it IS compatible with "natural" brake fluid, thus you need not do a complete flush to put it in your system. Anyone lame enough to use the silicone stuff today [with alternatives available] deserves what they get. Now, granted, you're not talking about putting it in a brake system, but I just wanted to point out that it ain't necessarily silicone...

We've been immersing electronics in oil for decades. Difference is, we build sonar systems, so we're doing it so the electronics can survive a high-pressure environment, and also because oil provides lots of heat sinking and you don't want to put fans and such in a sonar receiver. Like others have posted, though, it gets heavy: one of our units is only about as big as a Shuttle XPC box but weighs over 75 pounds.

I haven't seen the rancid oil problem, but we've only used a couple kinds of oil: a synthetic type (I'm told it's often used as a base for cosmetics), and castor oil. I have seen circuits change their operation when submerged (due to increased capacitance), but only once: a microprocessor reset controller changed its timing (it used a capacitor connected to a pin to determine how long to wait before letting the machine out of reset). You just have to be careful and watch for these things when designing the circuits.

Water leaks are bad, though water will tend to head down to the bottom. Our equipment is usually made to much tighter specs than any PC case, though (titanium housings and electron-beam welding, and sometimes an anti-corrosion coating). You get what you pay for.

A couple of things we deal with that your average PC builder won't: we have to forgo the use of any component with air inside it (e.g. aluminum can-type capacitors, some clock oscillator chips, really big power transistors), since they'll collapse under pressure (thousands of pounds per square inch), and we have to put a flexible window (or something similar) on one side of the enclosure because the oil volume will change with temperature.

Also... that oil gets on everything, man. No fun to work with. At least it doesn't smell too bad when you have to solder through it. But your hands feel greasy for the rest of the day, even after washing them.

As thousands of Slashdot users hammered the newly setup web server cooled by cooking oil the processor quickly heated up to previously unseen levels. This resulted in the server caking the cooking oil and quickly overheating as it crumbled under the/. effect.
Okay....the server is still up....but it is running a bit slow.

De-ionized water is a great non-conducting liquid, and in theory it would be a perfect bath for electronics. Unfortunately it's also a great solvent, and once particles start becoming dissolved, it becomes more and more conductive. It doesn't take a whole lot of conductivity to start arcing across solder pads with distances measured in fractions of a millimeter.

Definately not the dumbest idea I've ever heard -- making a hat out of a plastic bag, for example, would be worse.

There's really no point to posting this, true. It's not news. It is, however, making the internet rounds.
It's on the front page of reddit [reddit.com] and digg [digg.com]. It's probably elsewhere. The internet "news" sites tend to share quite a number of the same silly stories.

Normally hard drives require air for the read heads to maintain a proper height above the platters. Additionally, the heads would probably break if they were quickly moved through a viscous medium like oil. As far as I know, hard drives aren't completely air tight. Any ideas why this wasn't a problem?

Yes. Look at the absolutely first picture on page 1 in the article. What is sitting on top of the power supply?

Which of course defeats the whole purpose, the power supply has a fan of its own.

Nope, there's an air hole on every HDD. Just look at it, it's right there.

Of course on the inside of the case behind that hole there is a filter that keeps the particulate matter out of the drive (although some drives use very bad filters). You have to do this or you can end up with the drive warping as the outside pressure flucuates (like say, when you're shipping it to someone who's house is at a different altitude and temperature than your factory).

No.Fluorinert is expensive, and highly volatile, all the more when heated.You'd need a sealed system, with a heat exchanger somewhere.I worked for Cray, saw a Cray-2 system, and can assure you that (save for the coolness factor) you don't want one at home;)